Conservatories: practical construction considerations and design solutions help build perfect conservatories - indoor gardening facilities - Cover Story

Flower & Garden Magazine, Feb-March, 1994 by Alan Bertram

Conservatories Provide a Relaxing and Spacious atmosphere different from any other room in the house because of their light "no-roof" feel. In a conservatory, you can extend the pleasure of gardening to 12 months of the year.

Gardeners have been enthralled by these unique plant-filled environments for centuries. As far back as two thousand years ago, the Romans feasted and entertained in garden banquet rooms. Centuries later, English greenhouses were copied after those in Germany; they owed their existence to the craze for growing orange trees, which needed protection from the cold climates in the winter months. Instead of glass fittings, these original structures had wooden shutters that had to be removed in the milder months. Often the orange trees died during winter from lack of light.

Architectural "orangeries" -- still seen in continental Europe, such as the often romanticized French conservatories -- became the fashion in the first half of the 18th century. They were used for grand occasions and banquets, and designed to blend with the large country houses to which they were attached. At this time, glass was costly and of poor quality. Not until the later stages of the Industrial Revolution, when glass of better quality became available, did cast iron and glass structures become a viable proposition.

The houseplant craze of the 1970s gave another boost to the popularity of sunrooms and home conservatories. They have since become a very fashionable home extension, a blending of the garden and the house.

Basically, a conservatory is a glass building supported by a framework of metal or wood. Those built of aluminum are generally better suited for horticultural use, as they are thinner and lighter in construction. Plastic has become very popular over the last few years, but in most instances appears to be too sterile a material to use in a natural environment. Wood is the favored choice of many conservatory builders; it has a lasting quality and natural beauty perfectly suited for a plant environment. Wood is also a better insulator than aluminum, and causes less stress on the structure during variations in temperature.

Although modern conservatories are usually not as big as those of Victorian times -- some were so grand that horse-drawn carriages could be driven between the rows of palms -- they are still built on the same principle. Because of modern materials such as seasoned wood, improved paints and better glass, however, the new structures require much less maintenance.

An investment in a conservatory can be substantial, however, so prospective conservatory owners should think carefully about the practical aspects before the dream of a plant-filled room can become reality. As a conservatory is a unique construction project, it is advisable to engage a specialized contractor to ensure the structure is sound and built to last.

During the design stage with your specialist contractor, plan to make your conservatory large enough to accommodate the plants you wish to grow. But even so, small spaces should not discourage you from having a conservatory. An area as limited as a balcony may be successfully turned into a suitable conservatory.

In most cases, the foundation is the most obvious consideration and a very important but unseen part of the equation. Concrete floors may house heating elements and will act as a thermal storage radiator, absorbing heat throughout the day and gradually releasing it later in the evening.

If the conservatory is to be used as a plant house only, then the interior design will be different from one that will double as a sitting or dining area. Conservatories used solely for growing plants usually have tiled floors since they are practical and allow for the spillage of water. Furniture made of iron or wicker is a sensible choice for the plant house. Garden-type conservatories also intended as living space may have wooden floors, with or without carpet or area rugs, and comfortable upholstered seating. When installing wooden floors in a building constructed from glass, however, it is important to consider the possible buildup of heat and the resulting shrinkage and expansion in the width of the floor boards.

The glass panes, or glazing, may go right to the floor, but many people prefer to have lower brick or stonework walls that match the appearance of adjacent existing structures. Timber bottom panels may be employed as an alternative, and may blend better if constructed next to a house with wooden siding.

The types of timber most suitable for building a conservatory are western red cedar, redwood and pressure-treated lumber, the former being more rot resistant but very easily damaged. Whichever timber is chosen, it must always be stained or primed and painted in the controlled environment of a workshop, preferably where it has been manufactured. This consideration also applies to all woodwork in the construction. Stains and paints that allow the timber to breathe last much longer than conventional paints and do not peel, crack or flake.